Conventionally, as a cutter for cutting a concrete and a tile block, a disc grinder having a safety cover has been proposed for preventing dusts or cutting chips from being scattered. The disc grinder has a rotation shaft to which a circular blade is fixed. The safety cover is disposed over an outer peripheral edge of the circular blade. However, the dust or cutting chips may still be scattered even by the employment of the cover, to lower visibility and working environment in a working spot, particularly at an indoor working spot. Thus, the worker must wear a dust-protective mask and protective glasses.
In order to avoid this problem, Japanese Patent Application Publication No. 2002-46018 discloses a cutter in which one end of a dust collection hose is attached to a part of a cutter in fluid communication therewith. Another end of the dust collection hose is connected to an external electric dust collector. With this arrangement, residues and sawdusts generated during cutting operation are removed and collected into the duct collector through the hose. Alternatively, a dust collection bag can be used in combination with a vacuum device fluidly connected to the cover.
FIG. 14 shows a cutting state in a conventional cutter provided with a dust collection arrangement. A cutter 102 has a dust collection cover 101 in which a circular blade 104 is rotatably disposed. The cutter 102 cuts a workpiece 103 in a direction 109 while the circular blade 104 is rotated in a direction as indicated by an arrow in FIG. 14.
The dust collection cover 101 is attached with a suction sleeve 112 in fluid communication with an electric dust collector through a dust collection hose 120. A dust collection bag (not shown) is attachable to and detachable from the suction sleeve 112 so as to accumulate in the bag the dust discharged from the suction sleeve 112.
In the cutting operation for cutting the workpiece 103 with the cutter 102, the dust collection cover 101 and the cutter 102 are moved in the cutting direction 109. In this case, generated cutting dusts in the dust collection cover 101 are oriented toward the suction sleeve 112. The dusts are removed into the electric dust collector through the hose 120. Thus, scattering of the dust can be efficiently avoided.
However, since the dusts are directed in the cutting direction 109, a part of the protection cover 101 must be disposed at a leading end side thereof in the cutting direction. Accordingly, the leading end side of the protection cover 101 impedes a visibility to the blade edge.
In order to overcome this problem, another conventional cutter has been proposed as shown in FIG. 15 having a dust collection cover 201, a circular blade 204, and a suction sleeve 212. Cutting dusts are directed in a direction indicated by an arrow 205 which is opposite to a cutting direction indicated by an arrow 206. With this arrangement, it is unnecessary to largely cover a leading end side of the blade edge in the cutting direction 206, and therefore, the cutting edge at the leading end side can be observed.
Still however, the generated cutting dusts are not directed toward the suction sleeve 212, but are ejected into a cut groove 208 of the workpiece 203, thereby degrading dust collection efficiency.
It is therefore, an object of the present invention to provide a dust collection cover and a cutter provided with the same capable of enhancing dust collection efficiency without degrading visibility to the cutting edge.